1. Field
The invention relates to three-dimensional integrated automotive radars and methods of manufacturing the same. More particularly, the invention relates to a three-dimensional array antenna on a substrate with enhanced backlobe suppression for mm-wave automotive applications.
2. Background
Automotive radar systems are currently being provided in many luxury automobiles. Over the past few years, automotive radar systems have been used with intelligent cruise control systems to sense and adjust the automobile's speed depending on traffic conditions. Today, automotive radar systems are being used with active safety systems to monitor the surroundings of an automobile for collision avoidance. Current automotive radar systems are divided into long range (for adaptive cruise control and collision warning) and short range (for pre-crash, collision mitigation, parking aid, blind spot detection, etc.). Two or more separate radar systems, for example, a 24 GHz short range radar system and a 77 GHz long range radar system, which are typically each 15×15×15 centimeters in dimensions, are used to provide long and short range detection. Typically, the front-end (e.g., the antenna, the transmitter and the receiver) of an automotive radar system has an aperture area for the array antenna of 8 centimeters×11 centimeters and a thickness of 3 centimeters.
Prior art automotive radar systems have several drawbacks. For example, since multiple prior art radar systems are separately mounted on a vehicle, significant space is needed and can be wasteful. The cost for packaging, assembling, and mounting each radar system increases due to the additional number of radar systems. In order for each radar system to work properly, the materials placed on top of each radar system needs to be carefully selected so that the materials are RF transparent. The cost for multiple radar systems is further increased because multiple areas of RF transparency are needed on the front, sides, and rear of the vehicle. Thus, increasing the number of radar systems increases the packaging, assembly, mounting, and materials costs.
Therefore, a need exists in the art for a compact three-dimensional integrated array antenna for mm-wave automotive applications fabricated on low cost substrates.